From c0caf1a24cb9022d6259e0f4f42c332d9ad787b7 Mon Sep 17 00:00:00 2001
From: GnomeZworc <nicolas.boufidjeline@g3e.fr>
Date: Mon, 18 May 2026 22:49:21 +0200
Subject: [PATCH] f-28: add GetDefaultGateway to netif

Signed-off-by: GnomeZworc <nicolas.boufidjeline@g3e.fr>
---
 internal/netif/gateway_linux.go | 23 +++++++++++++++++++++++
 internal/netif/gateway_other.go | 12 ++++++++++++
 2 files changed, 35 insertions(+)
 create mode 100644 internal/netif/gateway_linux.go
 create mode 100644 internal/netif/gateway_other.go

diff --git a/internal/netif/gateway_linux.go b/internal/netif/gateway_linux.go
new file mode 100644
index 0000000..7636b7a
--- /dev/null
+++ b/internal/netif/gateway_linux.go
@@ -0,0 +1,23 @@
+//go:build linux
+
+package netif
+
+import (
+	"fmt"
+	"net"
+
+	"github.com/vishvananda/netlink"
+)
+
+func GetDefaultGateway() (net.IP, error) {
+	routes, err := netlink.RouteList(nil, netlink.FAMILY_V4)
+	if err != nil {
+		return nil, fmt.Errorf("list routes: %w", err)
+	}
+	for _, r := range routes {
+		if r.Dst == nil && r.Gw != nil {
+			return r.Gw, nil
+		}
+	}
+	return nil, fmt.Errorf("no default gateway found")
+}
diff --git a/internal/netif/gateway_other.go b/internal/netif/gateway_other.go
new file mode 100644
index 0000000..764867c
--- /dev/null
+++ b/internal/netif/gateway_other.go
@@ -0,0 +1,12 @@
+//go:build !linux
+
+package netif
+
+import (
+	"fmt"
+	"net"
+)
+
+func GetDefaultGateway() (net.IP, error) {
+	return nil, fmt.Errorf("not supported on this platform")
+}